Did my interview today in Austin, TX. I arrived 15 minutes early for my scheduled appointment and they were able to see me right away. They didn't seem too busy, so walk-ins might be available? I didn't ask, though, since I had a scheduled time and nobody else was waiting. The whole process was quick and painless. Finding a parking spot took longer than the actual interview. However, I noticed the person in the room next to me had arrived before I did and was still being questioned when I left, so YMMV. Good luck, fellow travelers!